Filter tubes adapted to filter fluids, such as gases or liquids, typically are mounted, with or without support cores, in one or more filter tube holders within an external housing to form a filter tube unit or assembly. The costs of the materials used in the holders and the manufacture of the filter tube holders and external housing are often quite expensive, so that the filter tube unit or assembly is usually desiged for long-term use, with only the filter tube being the disposable or replaceable element. However, there is a need for a simple, inexpensive, small, easily fabricated filter tube unit which would be disposable. Such a filter tube unit of complete expendability would be required or necessary for some filtering operations, and such units would constitute a great convenience and saving in other filter operations.